There has been a demand for high-frequency devices used in mobile phones and the like to be smaller in size. High-frequency devices, such as a filter, a duplexer, and the like that use surface acoustic waves (SAW), have been contributing to reducing the size of mobile phones with their features such as their small size and light weight. However, there has been a demand for further reduction in size and higher performance. Reducing the size of filters and duplexers reduces the distance between wires adjacent to each other, and may form a parasitic capacitance between the wires. When a parasitic capacitance is formed between wires, there is a risk that filter characteristics degrade.
Patent Document 1 discloses that in order to reduce a parasitic capacitance formed between wires, an insulating pattern is formed with a resin or the like on a substrate, and that a wiring portion is formed thereon.